The three primary colors by the subtractive color process are now used in silver halide color photographic materials, and color images are formed by combination of three dyes derived from a yellow coupler, a magenta coupler and a cyan coupler.
As magenta couplers used in conventional silver halide color photographic materials, pyrazolone type, pyrazolinobenzimidazole type or indanone type couplers are known, especially a variety of 5-pyrazolone derivatives are widely employed.
As a substitutent at the 3-position of the 5-pyrazolone ring of such 5-pyrazolone derivatives, there is used, for example, an alkyl group or an aryl group, the alkoxy group described in U.S. Pat. No. 2,439,098, the acylamino group described in U.S. Pat. Nos. 2,369,489 and 2,600,788, or the ureido group described in U.S. Pat. No. 3,558,319. These couplers, however, have defects in that they cannot provide high density magenta dye images due to their low coupling activities with an oxidation product of a developing agent, and in that magenta dye images formed by color development have a large secondary absorption in the blue light region and their primary absorptions are not sharp in the long wavelength region.
The 3-anilino-5-pyrazolone type couplers disclosed in U.S. Pat. Nos. 2,311,081, 3,677,764, 3,684,514 and British Pat. Nos. 956,261, 1,173,513 have a high coupling activity and a high color forming property, in addition to the advantage that useless absorption in the red light region is small. However, the primary absorption of these existing 3-anilino-5-pyrazolone type couplers is in a relatively short wavelength region. Therefore, when these are used in a color nagative silver halide photographic light-sensitive material, color reproducibility in printing is lowered, and large yellow stains appear on non-colored portions of a processed light-sensitive material in a long-term storage under high humidity conditions.
Various studies have been made to remove such defects. For example, Japanese Pat. O.P.I. Pub. No. 80027/1977 proposes use of 1-pentahalogenophenyl-3-anilino-5-pyrazolone type couplers. These couplers have a high coupling activity, a high color forming property and a good spectral property, but are low in dispersion stability because of their low solubilities in high-boiling organic solvents and, thereby, are liable to deposit as crystals while these are made into a dispersion or stored as a dispersion. In addition, these have a defect that magenta dye images formed by color development are unstable and undergo a large density change in the course of a long-term storage under high humidity conditions.